Paper tension and registration apparatus

ABSTRACT

Apparatus for adjusting the phase relationship between a combination of shafts which are rotated by a common endless loop drive means. The combination of shafts may advance web material of indeterminate length, such as paper from a roll and/or advance a web and an endless format tape controlling the advance of the web. Adjusting the phase relationship between the shafts results in a corresponding change in the tension of the web being advanced and/or in the registration between the web and the format tape, respectively. Specifically, a pulley arrangement varies the respective lengths of the parts of the drive means between the shafts, and one shaft experiences a different rotation or phase adjustment relative to the other.

United States Patent 72] Inventor Raymond A. Skiba Detroit, Mich.

[2 l Appl. No. 789,341

[22] Filed Jan. 6, 1969 [45] Patented Mar. 16, 1971 [73] Assignee Burroughs Corporation Detroit, Mich.

[54] PAPER TENSION AND REGISTRATION APPARATUS 3 Claims, 4 Drawing Figs.

[52] U.S. Cl 226/108, 226/9, 226/195 [5l] 1nt.Cl B65h 23/18 [50] Field of Search 226/l08, 76, 9, l95, 25; 60/24 (lnquired) [56] References Cited UNITED STATES PATENTS 3,154,233 10/ 1964 Hubbard et al. 226/9 3,381,867 5/1968 Konkel ABSTRACT: Apparatus for adjusting the phase relationship between a combination of shafts which are rotated by a common endless loop drive means. The combination of shafts may advance web material of indetennnate length, such as paper from a roll, and/or advance a web and an endless format tape controlling the advance of the web. Adjusting the phase relationship between the shafts results in a corresponding change in the tension ofthe web being advanced and/or in the registration between the web and the format tape, respectively. Specifically, a pulley arrangement varies the respective lengths of the parts of the drive means between the shafts, and one shaft experiences a different rotation or phase adjustment relative to the other.

PAENEnuAmemn 3,570,735

-snmlnrs' INVENTOR.

RAYMOND A.. SKIBA 'swf/M AGENT PAPER TENSHON AND REGESTRTION APPARATUS BACKGROUND OF THE INVENTION This invention relates generally to adjusting the phase or amount of rotation between at least two rotating members. lt is particularly useful when employed in conjunction with a machine for advancing web material of indeterminate length through a work area for performing operations on the web material under the control of a format on an endless tape. rfhese operations on the web material may takeA several forms. lt may be desired, for example, to cutor punch the material, or to'print on the material. Usually, these operations are performed on the web material by moving it relative to a work station. In view of this particular utility the invention will be described as being incorporated in one species of such a machine a high-speed printer used as the output of a data processing system.

. There have been many recent advances in high-speed printers where the web, or paper, is advanced through `the printing area line-by-line under the control of a format tape. Electromagnetically operated clutches have been utilized to control the amount and speed of the paper advance, and an electromagnetically operated brake has been employed to stop paper motion'. An example of this type of machine is more fully described in the copending application of Funk et al. Ser. No. 784,685, filed Dec. 18, l968,entitled Dual Speed Paper Advance with Skip to Format Heading" and assigned to the assignee of the present invention.

Present day high-speed printers, operating at printing speeds in excess of 800 lines per minute, require a web feed mechanism which both advances the web and maintains proper web tension. Proper tension is required to prevent tearing of the web from the change in longitudinal stress caused by the rapid acceleration and deceleration of the web and also to provide a high quality printed output. in addition, proper registration is required between the format tape and the web to insure that the printing on the web maintains proper vertical alignment. This is particularly important when printing on a bill, check, ledger sheet or other form.

ln high-speed printers the web or paper is usually perforated and is gripped and advanced by sets of flexible endless tractors, each tractor having pins for positive engagement with the perforations in the paper. Generally two sets of tractors are employed, one set on each side of the printing area, thereby providing positive control of the paper as it is advanced through the printing area. Both sets of tractors and the format tape are usually driven in synchronism, and information on the format tape controls the intermittent advance of the paper.

ln order to maintain high quality printing it is necessary to provide for adjustment of the paper tension in the printing area. A coarse adjustment of the tension is inherently provided since the positive engagement ofthe tractor pins and the paper may be changed from one set of perforations to another set of perforations. However this is a time-consuming adjustment lbecause it may only be performed when the machine is stopped. Furthermore the desired adjustments in paper tension are usually less than the distance between adjacent perforations. An example of a machine which provides fine adjustment of the paper tension is found in US. Pat. No. 3,152,742, Wright, assigned to the assignee of the present invention. As the paper is advanced through the printer a different rotation is imparted to the lower drive shaft relative to the upperdrive shaft to adjust paper tension. The Wright patent, however, is used in a printer in which the paper tractors are driven in synchronism by a drive shaft, as distinguished from the belt driven system of the present invention.

Similarly, in order to maintain strict vertical alignment of the lines of printing, it is necessary to regulate the registration.

between the control information on the format tape and the paper in the printing area. Again a coarse adjustment is inherently provided since the format tape may be disengaged from its drive means and reengaged in a slightly different position. This suffers from the same problems as the coarse adjustment of paper tension discussed in the preceding paragraph and, therefore, a fine adjustment which may be utilized while the machine is operating is desired.

High-speed printers using a toothed belt to drive the tractors and thereby advance the paper are well known in the art. in the past some of these belt-driven printers utilized separate belts for each set of tractors and separate belts linking each set of tractors with a motor, while others utilized one belt linking both sets of tractors and a second belt linking the motor to one set of tractors. Adjusting these belts to change the paper tension requires extra pairs of pulleys -which results in sharp turns of the belt around the pulleys, thus shortening belt life and providing a less positive response because of the complex geometrical arrangement of the pulleys. Adjustingpaper tension in these printers is additionally hard on the belts because it often increases the tension in one segment of the belt without corresponding adjustment to relieve this belt tension. This effects a stretching of the belt thereby shortening belt life and increasing maintenance requirements of the entire printer system.

SUMMARY It is accordingly an object of the present invention to provide a new and improved apparatus for adjusting the phase relation of commonly driven rotating shafts.

Another object of the invention is to provide an improved apparatus for adjusting paper tension in a high-speed printer.

lt is another object of my invention to provide an apparatus for adjusting registration between the format tape and the paper in a high-speed printer.

lt is a further object to provide a paper tensioning and regis tration apparatus which utilizes a simpler geometrical configuration thereby providing more positive control of paper tension and registration, less wear and tear von the drive means and greater reliability.

These and other objects are accomplished in a system having a single belt drive and :at least two rotating shafts, by providing means for lengthening one segment of the belt and shortening another segment of the belt relative to the paths of the belt. The additional length is passed around one shaft from the longer segment to the shorter segment causing that shaft'to rotate a different amount relative to the other shaft. lf the rotating shafts advance the same material the result is an adjustment of the tension of the materiai being advanced; if the shafts advance different materials the result is an adjustment of the registration between the materials. lnthe preferred embodiment, as in most instances, it is desirable to be able to ad just the tension independently of the registration or the registration independently of the tension or both. The apparatus includes a plate, preferably mounted on one shaft, and idler rollers or guide means mounted on the plate'. When the plate isA part of the present specification. For a better understanding of the invention, its advantages and the specific objects attained withits use, reference should be had to the accompanying drawings and descriptive matter.

BRIEF DESCRIPTEON 0F THE DRAWINGS in the drawings, wherein like reference numerals designate `corresponding parts;

HG. l, is an overall perspective view of part of a high-speed printer controlled by format information on a tape, in which the subject of this invention is shown as a part thereof;

FlG. 2 is a side view of a portion of the printer of FlG. i showing the improvement which is the improvement which is the subject of this invention;

FIG. 3 is a side view of a portion of the printer of FIG. l., showing, in greater detail, a portion of the adjusting apparatus of Fi-G. 2; and

FIG. 4 is a cross-sectional view taken along line 4 4 of FIG. 3 showing the detailed structure of the apparatus described herein.

DESCRIPTION OF THE PREFERRED EMBOQIMENT FlG. l shows generally the elements of a high-speed printer associated with data processing equipment. Paper il of indeterminate length is advanced through the printing machine by two sets of drive tractor assemblies. The upper set of drive tractors i3 is driven by the square drive shaft 25 and is supported by shaft 2i. A lower set of drive tractors l5 is driven by a similar square drive shaft 27 and shaft 23 supports the lower tractor assembly. Each of these four drive tractors includes an endless flexible belt carrying paper-engaging pins 17. The pins are spaced around each of the drive tractor belts and are shown at the left lower drive tractor l5. The pins engage the margin holes or perforations 19 of paper 11 with pressure plate M of eacii tractor assembly holding the paper secure to assure penetration by the pins. The location of the four drive tractors defines the work area ofthe high-speed printer.

Format tape 101, which controls the paper advance as disclosed in the aforementioned copending application of Funk et ai. is driven by sprocket 99 in synchronism with paper li, and carries control information which determines where the paper shall be stopped to receive printing. Conventional tape reader 97 converts the infomation on format tape 101 into electronic pulses in a well-known manner. The pulses control a source of motive power (not shown) to drive pulley 28 which drives pulley 35 by a power transmitting belt 34. Shaft di is journaled in a sprocket 99 and is joumaled in wheei 39. Drive belt 33, driven by pulley 35, advances the paper and the format tape in synchronism as will be described in detail hereinafter.

The printing station, (not shown), defined by the upper and lower sets of drive tractors, is generally of a well-known variety employing a rotating drum type carrier on one side of paper il and electromagnetically controlled print hammers on the other side of the paper. To obtain proper printing the paper il, when it is between the upper and lower drive tractors, should have a certain amount of tension. Paper tension may be manuaiiy adjusted by removing the paper from one set of tractors and sliding it so that different holes i9 are in contact with pins on each of the tractors. However, it is desirable to obtain a finer adjustment of the paper tension for reasons previously indicated. lt can be seen that if either drive shaft or 27 is rotated slightly relative to the other shaft the tension of paper 11 between the upper and lower tractors will be affected.

Upper drive pulley 29 has teeth to engage toothed belt 33, and upper square drive shaft 25 is journaled in pulley 29. When drive pulley 29 is rotated by belt 33 it imparts motion to the upper set of drive tractors i3. Similarly, lower square drive shaft 27 is joumaled into toothed drive pulley 3l, and when drive belt 33 causes pulley 3l to rotate, motion is imparted to the lower set of drive tractors 15. Since belt 33 is common to these two drive pulleys the upper and lower tractor pairs are driven in synchronism.

FIG. 2 shows the end view of the paper tension and registration apparatus of FIG. 2. To advance the paper, belt 33 drives pulleys 29 and 3l which, in turn, rotate shafts 25 and 27, respectively, for example, in a counterclockwise direction. By changing the phase relationship or phasing between shafts 25 and 2? a corresponding change in the paper tension will result. Applicant has provided a new and improved means for changing the angular rotation of one shaft with respect to the other shaft. Although this may be accomplished either while the belt 33 is moving or stationary the principles of the invention will be described while the belt is moving.

Assume the belt to be moving at a speed such that shafts 25 and 27 and pulleys 29 and 3l are rotating in the counterclockwise direction at a fixed speed of w radians per second. (If-@F0 it is equivalent to the paper being stopped). To change the phase relation between shafts 25 and 27 it is necessary to change the amount or" rotation of one shaft, for example shaft 27', by an amount 100. According to the standard formula for rotational movement 6=wl, therefore, during a fixed time interval t, shaft 25 will rotate through an angle 025=wt and shaft 27, because of the desired phasing 0o, will rotate @zr-uti =6250.

With paper il being advanced by the connterclockwise rotation of shafts 25 and 27, if 6 is in the counterclockwise direction the lower shaft rotates an additional amount 6 relative to the upper shaft, and the lower tractors rotate an additional amount 6 relative to the upper shaft, and the lower tractors rotate an additional amount 0 relative to the upper tractors.

Therefore, more paper is fed into the print area by the lower tractors than is removed by the upper tractors. This amount is directiy proportional to 9a, and the extra paper in the print area results in less paper tension. Clockwise rotation of the shaft 27, on the other hand, feeds less paper into the print area relative to the speed of the upper drive tractors thereby increasing paper tension.

To effect this phasing l have invented a novei pulley arrangement which is connected to the lower drive shaft 27. Plate 5l is rnounted on shaft 27 to rotate independently of the shaft. Idler rollers 47 and L39, also mounted on plate 5l, have timing belt 33 looped around them such that the path of the belt from roller 49 around pulley 3l to roller 47 forms a bight. To explain the operation of this apparatus consider the belt 33 as having two segments or sections; the first segment being from pulley 29 around roller 47 to pnlley 3l and the second segment being from pulley 29 around roller 49 to pulley 31. By a clockwise rotation of plate 51 the pressure from roller 47 against the first belt segment will decrease, making the first segment longer by an amount X than the path it travels, while the corresponding increase of pressure from idler 49 against the second belt segment makes the second segment shorter by an equal amount X than the path it travels.

ln response to the rotation of plate 5l. in the clockwise direction, drive pulley 3! is rotated in the clockwise direction by belt 33 as the length X is passed from the lirst segment of belt 33 around pulley 3l to the second segment of belt 33. Moving plate 5l in this direction will tend to increase the tension on paper 11 since the rotation of pulley 31 opposes the normal rotation for paper advance. Rotating plate 5l in a counterciockwise direction, on the other hand, will have the effect of decreasing the tension of the paper 1l between the upper and lower sets of drive tractors.

Existing paper-tensioning mechanisms that eect an adjnstment in belt segments on both sides of a paper drive pulley utilize four idler roiiers on a common support separate from the drive shaft. Adjusting this type of mechanism causes sharp bends in the belt which will shorten its useful life. The unique simplified geometric configuration of this invention using only two idlers or rollers mounted on the drive shaft, provides greater reliability and a more positive response to the rotation of plate 5 l.

Since the change in lengths of the two belt sections is equal there will be no change in the tension of the belt between the extremes of the adjustment. This is desirable in order to prevent stretching of the belt. The extremes of the adjustment, which are the limit that plate 5l may rotate, must be carefully determined in order tckeep the change in belt segment lengths equal. A stud 57, positioned in the printer frame 67, cooperates with an oversize hole 55 in piate 5i to limit the rotational movement of the plate 5l. FIG. 3 illustrates the cooperation between stud 57 and the periphery of aperture 5S when plate 5i has been rotated to the limit of counterclockwise rotation. if this rotation is insufficient to eect the necessary paper tension the machine should be stopped, the

pressure plates Ml should be released, and the paper il realigned on the pins 17 Referring to FIGS. 2, 3 and 4, for a detailed description of the pulley assembly, shafts 63 and 65 are joumaled in rollers 47 and 49, respectively. The shafts are mounted on plate 5l. A ring-shaped housing 59 is secured to machine frame 67 coaxially to drive shaft 27. A ring bearing 6l allows the plate 5l to be rotated about the axis of shaft 27 independently of housing 59 and frame 67. Control shaft 69 includes a helical gear 7l intermediate its ends which engages teeth 73 of the plate Sil. Knob 53 is attached to shaft 59 and by turning knob 53 to rotate shaft 69, gear 7l cooperates with teeth 73 to rotate plate 51. The control shaft 69 is joumaled in retaining blocks 75 and 77 which are attached to machine frame 67. An enlarged portion 79 of shaft 60 is retained by washer 81 and locltnuts d3 and 85 against block 77 to prevent the shaft 69 from having any substantial axial movement.

Lower paper tractor drive shaft 27 is joumaled in a housing 89 and allowed to rotate independently of Plate 5l. The square tractor drive shaft 27 is fitted with a cylindrical sleeve 87 in order to provide a round surface for contact with beatings 91. Drive shaft 27, sleeve 87 and drive pulley 3l are maintained in position for simultaneous and equal rotation by pin 93.

lt is often desirable to have an adjustment on shaft 69 to vary the amount of torque necessary to turn the shaft for rotating plate 5l. boclcnuts 83 and 85 allow adjustment of the frictional engagement of the shaft 69 with retaining block. 77. Added torque is obtained by tightening nut S3 which induces a force on the faces of frictional washer 8l. When the desired torque is obtained, nut 85 is tightened .against nut 83 to lock the latter in plate.

The use of changing the phase between two rotating shafts has been described in an embodiment wherein the tension of the paper being advanced is adjustment. However, it often may become necessary to change the phasing between two shafts which are driving different materials. This may be true in format-controlled machinery such as an assembly line or in a high-speed printer, when, for example, a change in timing or registration becomes necessary. Referring again generally to FIG. l, it will be seen that drive shaft 4l, which rotates with gear 39, drives the sprockets 99 to advance the format tape im. Since belt 33 is common to the paper advance gears 29 and 3ft and to gear 39, the format tape is driven in synchronism with the advance of the paper li.

Referring again to FIG. 2, where primed reference numerals indicate components having the same functions as their nonprimed counterparts (e.g., plate 5l' having a pulley arrangement mounted thereon corresponds to plate 5 i having the pulley arrangement previously discussed), gear 39 is mounted on a plate 5l' along with rollers 47' and 49. Drive belt 33 is looped around roller 47 drive gear 39, and roller 49 to form a bight with the drive gear 39 in the center of the bight.

Shaft 63' is joumaled in roller 47 and shaft 65 is joumaled in roller a9' and the shafts are mounted on plate 5l Shaft 4l, joumaledv in drive gear 39, is mounted on plate 51', and plate 511 is mounted on frame 67 and is capable of rotation independent of' shaft di. Therefore, in a manner similar to that described with respect to the idler arrangement of plate 5i, if it is considered that belt 33 is moving in a counterclockwise direction, counterclockwise rotation of plate 5l' will effectively lengthen the segment of the belt by an amount X from gear 29 past roller 47 to gear 39 and will effectively shorten the segment of the belt from drive gear 35 past roller 49 to drive gear 39 by an equal amount X. Then, as in the description with respect to rotation of plate 51, gear 39 will be advanced an additional amount as the change in the belt length X passes around gear 39, thereby increasing the distance that the format tape moves by a phase change i0., as in the prior discussion. Plate 5H' has an aperture 55 therein and limit stud 57' is mounted in frame 67 to limit the rotational 'motion of plate 5B The drive means for turning plate 5 i' is substantially. the same as the drive means for turning plate 5f. Here a knob 53' is mounted on one end of shaft 69 and a helical gear 7l' is mounted at the opposite end of the shaft. The gear engages teeth 73' in plate 5l' to rotate plate 51' with respect to the center of shaft 451. Retaining blocks 75' and 77' are mounted to frame 67 and the shaft 69' is journaled in the blocks. Locknuts S3' and 35' mounted on the shaft, maintain the shaft in alignment, and can be adjusted as in the Aadjustment of locknuts 83 and 85 tof modify the amount of torque necessary to rotate plate 5 l lf the printing is 1being placed-on a form and the lines of printing are too low, for example, it is necessary to print earlier" with respect to the position of paper ll. This may be ac.- complished by reading the format tape 101 earlier", in other words, imparting a phase change between paper drive gear 29 and format drive gear 39. lncreasing the rotation of gear 39 with respect to gear 29 by an amount 0 advances format tape 10i by an additional amount relative to the synchronous paper advance and causes the format tape information to be read earlier." This is effected by rotating plate 51' counterclockwise as previously explained with reference to plate 5l. Clockwise rotation of plate 51' has the opposite effect; delay.- ing format tape 101 by an amount proportional to the phasing 00 and lowering the lines of print.

This invention has been described in the environment of a high-speed printing machine. lt is obvious, however, that changing the angular rotation or the phase between two rotating shafts, whether or not they are driving the same material, may be incorporated in any machine where this function is desired. Our invention, therefore, should only be limited by the scope of the appended claims.

l claim:

l. ln a machine for advancing material through a work area and performing operations thereon under control of a format tape, the combination comprising:

a first drive shaft for advancing said material, said first drive shaft being located in advance of said work area;

a second drive shaft for advancing said material, said second drive shaft being located beyond said work area;

a third drive shaft dierent and distinct from said first and second drive shafts for advancing said format tape;

a single endless flexible drive means for imparting synchronous rotation to all of said drive shafts;

means for independently adjusting the tension of said material advancing between said first and second drive shafts and over said work area; and.

means independent of said tension-adjusting means for adjusting the registration between said material and said format tape.

2. The combination of claim l wherein said tension-adjusting means includes:I

first and second pulleys mounted on said first and second drive shafts, said endless flexible drive means being looped around said pulleys for imparting rotation to said shafts, said pulleys dividing said endless flexible drive means into two sections;

a plate mounted for rotational movement about one of said first and second drive shafts;

means for rotating said plate; and

guide means mounted on said plate for engaging said two sections, said guide means being responsive to said plate rotation for displacing the path of each of said two sections by substantially opposite deflections and varying the phase of one of said first and second drive shafts with respect to the other of said first and second drive shafts.

3. The combination of claim ll wherein said registration-adjusting means includes:

first and second pulleys mounted on said third drive shaft l and second drive shafts respectively, said endless flexible drive means being looped around said pulleys for imparting rotation to said shafts,4 said pulleys dividing said endless flexible drive into two sections; l

a plate mounted for rotational movement about said third drive shaft;

means for rotating said plate; and

tions by substantially opposite deflections and varying the phase of said third drive shaft with respect to said one of first and second drive shafts. 

1. In a machine for advancing material through a work area and performing operations thereon under control of a format tape, the combination comprising: a first drive shaft for advancing said material, said first drive shaft being located in advance of said work area; a second drive shaft for advancing said material, said second drive shaft being located beyond said work area; a third drive shaft different and distinct from said first and second drive shafts for advancing said format tape; a single endless flexible drive means for imparting synchronous rotation to all of said drive shafts; means for independently adjusting the tension of said material advancing between said first and second drive shafts and over said work area; and means independent of said tension-adjusting means for adjusting the registration between said material and said format tape.
 2. The combination of claim 1 wherein said tension-adjusting means includes: first and second pulleys mounted on said first and second drive shafts, said endless flexible drive means being looped around said pulleys for imparting rotation to said shafts, said pulleys dividing said endless flexible drive means into two sections; a plate mounted for rotational movement about one of said first and second drive shafts; means for rotating said plate; and guide means mounted on said plate for engaging said two sections, said guide means being responsive to said plate rotation for displacing the path of each of said two sections by substantially opposite deflections and varying the phase of one of said first and second drive shafts with respect to the other of said first and second drive shafts.
 3. The combination of claim 1 wherein said registration-adjusting means includes: first and second pulleys mounted on said third drive shaft and second drive shafts respectively, said endless flexible drive means being looped around said pulleys for imparting rotation to said shafts, said pulleys dividing said endless flexible drive into two sections; a plate mounted for rotational movement about said third drive shaft; means for rotating said plate; and guide means mounted on said plate for engaging said two sections, said guide means being responsive to said plate rotation for displacing the path of each of said two sections by substantially opposite deflections and varying the phase of said third drive shaft with respect to said one of first and second drive shafts. 